1. Field of the Invention
The present invention relates to the manufacture and test of optical fibers. More specifically, the present invention relates to systems for detecting inconsistencies in organic buffers on optical fibers.
While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
2. Description of the Related Art
As is known in the art, optical fibers typically have a glass filament core (comprised of a cladding surrounding a wave guiding core) which is surrounded by a protective sheath of organic material. Commonly referred to as the "buffer layer", this sheath often has bubbles, breaks, scratches and other nonuniformities which occur as a result of the fabrication and/or handling of the fiber. For most communication applications, such nonuniformities in the buffer layer have heretofore been thought to be eliminated. However, certain fiber optic applications place significant demands on the tensile strength of the fiber optic. One such stressful application is in the deployment of fiber during the flight of a fiber optic guided missile. In this case, the fiber may be stressed at levels approaching its intrinsic strength. Pre-existing defects in the coating may have permitted mechanical contact with the glass fiber. This could weaken the fiber such that it would be likely to break at stresses lower than the mechanical proof stress. The mechanical proof stress is estimated to be large enough to insure successful fiber payout.
Hence, a detailed inspection of the fiber is critical to assure the survivability of the fiber. Currently, this inspection is only performed manually with a microscope on the fiber ends. Unfortunately, with missile fiber lengths being on the order of tens of kilometers, this process is inadequate. Further, the inspection may have to be repeated to guarantee a rigorous control of fiber quality after handling and/or shipping.
Thus, there is a need in the art for a fast, inexpensive technique for inspecting the protective buffer on long lengths of optical fiber for defects and flaws.